Evolution

• What is the Hardy-Weinberg equation?

  P² + 2pq + q² = 1
• When can you use Hardy-Weinberg principles?

  When there is no mutation, random mating, no gene flow, and no selection
• What does genetic variation arise from?

  Mutations, meiosis, and random fertilization
• What other factors affect phenotypes besides genes?

  The environment
• What is polygenic inheritance?

  When multiple genes affect a single trait
• What are environmental factors that limit a species' population called?

  Selection pressures
• What is a gene pool?

  The total alleles of all genes in a population
• What is evolution?

  The change in allele frequency over time
• What is natural selection?

  Survival of individuals with advantageous alleles
• What is the process of natural selection?

  Random mutation leads to genetic variation and selection pressure
• How does variation play a role in natural selection?

  It allows some individuals to survive in new conditions
• What is the role of over-production of offspring in natural selection?

  It leads to increased competition and survival of the fittest
• What is stabilizing selection?

  Preserves average phenotypes by favoring average individuals
• When does stabilizing selection occur?

  When environmental conditions are constant over time
• What is directional selection?

  Favors phenotypes that vary in one direction
• When does directional selection occur?

  When environmental conditions change
• What is disruptive selection?

  Favors individuals with extreme phenotypes
• When does disruptive selection occur?

  When environmental factors take distinct forms
• What is a species?

  A group of organisms that can interbreed
• What is speciation?

  The evolution of new species from existing ones
• What does it mean when populations are reproductively isolated?

  There is no gene mixing between them
• What happens if populations are isolated for several generations?

  Genetic differences accumulate, leading to speciation
• What is allopatric speciation?

  Formation of species due to geographical isolation
• What prevents gene flow in allopatric speciation?

  Geographical barriers like rivers or mountains
• What is sympatric speciation?

  Formation of species due to reproductive isolation in the same area
• What are some prezygotic barriers for sympatric speciation?

  Ecological, temporal, and behavioral barriers
• What is continuous variation?

  Characteristics that change gradually
• What is discontinuous variation?

  Characteristics with a limited number of values